Chemical mechanical polishing composition for polishing silicon oxide substrate and polishing method thereof

Abstract

The invention provides a chemical mechanical polishing composition for polishing a silicon oxide substrate and a polishing method of the chemical mechanical polishing composition, and relates to the technical field of chemical mechanical polishing. The chemical mechanical polishing composition includes a first abrasive particle and a second abrasive particle. Wherein the first abrasive particles are needle-shaped cerium oxide abrasive particles; and the second abrasive particles are cerium oxide abrasive particles and are different from the first abrasive particles. The first abrasive particles and the second abrasive particles are matched, so that the chemical mechanical polishing composition has excellent planarization performance while improving the material removal rate.

Description

Technical Field

[0001] This application relates to the field of chemical mechanical polishing technology, and more particularly to a chemical mechanical polishing composition for polishing silicon oxide substrates and a polishing method thereof. Background Technology

[0002] In the manufacturing process of semiconductor devices, interconnect dielectrics (ILDs) are typically used for electrical isolation and structural support between multiple metal layers. Common ILD materials include silicon oxide dielectrics, among which tetraethyl orthosilicate (TEOS) is a widely used silicon oxide precursor, often deposited using processes such as chemical vapor deposition (CVD) to form amorphous silicon oxide dielectric layers.

[0003] In the formation of multilayer metal interconnect structures, to achieve good planarization and reduce subsequent pattern distortion and critical dimension changes, chemical mechanical polishing (CMP) is required to planarize the TEOS layer. An excellent ILD CMP process not only requires removing the TEOS surface layer while retaining the filling material in the trenches, but also achieving a small remaining step height to reduce trench loss and improve the overall surface morphology.

[0004] However, commonly used CMP compositions often suffer from low material removal rates (RR) due to the abrasive particles they contain, which affects process efficiency and prolongs the process cycle. Therefore, in practical applications, there is an urgent need to develop CMP compositions that can improve material removal rates while also possessing excellent planarization performance, in order to meet the stringent requirements of ILD planarization processes in advanced device manufacturing. Summary of the Invention

[0005] This application provides a chemical mechanical polishing (CMP) composition and a polishing method thereof for polishing silicon oxide substrates. The abrasive particles in the CMP composition are a mixture of needle-shaped cerium oxide particles and other cerium oxide particles different from needle-shaped cerium oxide particles. This allows the CMP composition to improve the material removal rate of the silicon oxide substrate while reducing the remaining step height.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0007] In a first aspect, embodiments of this application provide a chemical mechanical polishing composition for polishing silicon oxide substrates, comprising: a first abrasive grain, wherein the first abrasive grain is a needle-shaped cerium oxide abrasive grain; and a second abrasive grain, which is a cerium oxide abrasive grain and is different from the first abrasive grain.

[0008] According to some embodiments of this application, the second abrasive grain is a chamfered octahedral cerium oxide abrasive grain.

[0009] According to some embodiments of this application, the weight ratio of the first abrasive grain to the second abrasive grain ranges from 1:9 to 9:1, wherein the proportion of the first abrasive grain is between 10% and 90%, and the proportion of the second abrasive grain is between 10% and 90%.

[0010] According to some embodiments of this application, the weight ratio of the first abrasive grain to the second abrasive grain ranges from 3:1 to 1:3, wherein the proportion of the first abrasive grain is between 25% and 75%, and the proportion of the second abrasive grain is between 25% and 75%.

[0011] According to some embodiments of this application, the average length of the first abrasive grain ranges from 500 nm to 3000 nm, and the average length is measured by scanning electron microscopy.

[0012] According to some embodiments of this application, the average width of the first abrasive grain is in the range of 50 nm to 250 nm, and the average width is measured by scanning electron microscopy.

[0013] According to some embodiments of this application, the ratio of the cumulative volume of abrasive grains having an average particle size more than twice that measured by scanning electron microscopy to the cumulative volume of abrasive grains having an average particle size less than that measured by scanning electron microscopy in the second abrasive grain is at least 0.1.

[0014] According to some embodiments of this application, the coefficient of variation of the average particle size of the second abrasive grain, as measured by scanning electron microscopy, is greater than 30%.

[0015] According to some embodiments of this application, the second abrasive grain has a non-monodispersive particle size distribution, which is measured by scanning electron microscopy.

[0016] According to some embodiments of this application, the polydispersity index of the second abrasive grain, as measured by scanning electron microscopy, is at least 0.1.

[0017] According to some embodiments of this application, at least 0.5% of the second abrasive grains have a particle size greater than twice the average particle size as measured by scanning electron microscopy.

[0018] According to some embodiments of this application, the composition further includes a polishing aid comprising: a sugar alcohol, for enhancing the removal rate of the silicon oxide substrate.

[0019] According to some embodiments of this application, in the Raman spectrum excited by a 532 nm laser, the one-third full width at one-third (FWTM) of the F2g vibration peak of the needle-shaped cerium oxide abrasive grains is 30 cm⁻¹ to 200 cm⁻¹.

[0020] According to some embodiments of this application, in the Raman spectrum excited by a 532 nm laser, the one-third full width at one-third (FWTM) of the F2g vibration peak of the needle-shaped cerium oxide abrasive grains is 40 cm⁻¹ to 130 cm⁻¹.

[0021] According to some embodiments of this application, in the Raman spectrum excited by a 532 nm laser, the full width at half maximum (FWHM) of the F2g vibration peak of the needle-shaped cerium oxide abrasive grains is 10 cm⁻¹ to 100 cm⁻¹.

[0022] According to some embodiments of this application, in the Raman spectrum excited by a 532 nm laser, the full width at half maximum (FWHM) of the F2g vibration peak of the needle-shaped cerium oxide abrasive grains is 20 cm⁻¹ to 80 cm⁻¹.

[0023] According to some embodiments of this application, in the Raman spectrum excited by a 532nm laser, the full width at half maximum (FWHM) of the F2g vibration peak of the needle-shaped cerium oxide abrasive is greater than that of the F2g vibration peak of the second abrasive.

[0024] According to some embodiments of this application, in the Raman spectrum excited by a 532 nm laser, the one-third full width at first glance (FWTM) of the F2g vibration peak of the needle-shaped cerium oxide abrasive is greater than the one-third full width at first glance (FWTM) of the F2g vibration peak of the second abrasive.

[0025] According to some embodiments of this application, the composition further includes a polishing aid comprising: a sugar alcohol, for enhancing the removal rate of the silicon oxide substrate.

[0026] Secondly, embodiments of this application provide a polishing method for a silicon oxide substrate, the method utilizing a composition as described in any one of the first aspects above to polish the silicon oxide substrate. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1Visible Raman spectra of chamfered octahedral cerium oxide abrasive grains, needle-shaped cerium oxide abrasive grains A, and needle-shaped cerium oxide abrasive grains B provided according to embodiments of this specification are shown at an excitation wavelength of 532 nm.

[0029] Figure 2 A scanning electron microscope image of needle-shaped cerium oxide abrasive grains provided according to an embodiment of this specification is shown;

[0030] Figure 3 A scanning electron microscope image of uncalcined chamfered octahedral cerium oxide abrasive grains (purchased) provided according to an embodiment of this specification is shown;

[0031] Figure 4 A scanning electron microscope image of uncalcined chamfered octahedral cerium oxide abrasive grains (prepared) according to an embodiment of this specification is shown;

[0032] Figure 5 A scanning electron microscope image of calcined chamfered octahedral cerium oxide abrasive grains provided according to an embodiment of this specification is shown. Detailed Implementation

[0033] The following description provides specific application scenarios and requirements for this specification, intended to enable those skilled in the art to make and use the contents of this specification. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this specification. Therefore, this specification is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0034] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not restrictive. For example, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” used herein may also include the plural forms. When used in this specification, the terms “comprising,” “including,” and / or “containing” mean that the associated integers, steps, operations, elements, and / or components are present, but do not exclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or that other features, integers, steps, operations, elements, components, and / or groups may be added to the system / method.

[0035] In this application, "X includes at least one of A, B, or C" means that X includes at least A, or X includes at least B, or X includes at least C. That is, X can include any combination of A, B, and C, or any combination of A, B, and C, as well as other possible content / elements. The arbitrary combination of A, B, and C can be A, B, C, AB, AC, BC, or ABC.

[0036] Considering the following description, these and other features of this specification, as well as the operation and function of related structural elements, and the economy of assembly and manufacture of components, can be significantly improved. This description also includes all figures and text in the accompanying drawings, all of which form part of this specification. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification. It should also be understood that the drawings are not drawn to scale.

[0037] In current semiconductor manufacturing processes, especially during the formation of ILD structures, CMP (Chemical Metallurgy Processing) is a crucial technique. Its core objective is to remove excess dielectric material (such as silicon dioxide deposited via TEOS) from the trenches and areas above the silicon wafer surface, thereby achieving effective electrical isolation between devices and providing a highly flat surface for subsequent metal layer deposition. However, in existing technologies, CMP processes still face several key challenges that impact device performance.

[0038] First, the removal rate (RR) is one of the core metrics for measuring the efficiency of CMP processes. It refers to the thickness of material removed from the substrate surface per unit time. Currently, some commonly used CMP compositions, especially those for polishing silica-based materials, often have low RR due to their abrasive systems (such as silica). This leads to decreased production efficiency, reduced equipment utilization, and increased overall manufacturing costs.

[0039] Secondly, step height and residual step height are important parameters for evaluating the planarization capability of CMP processes. In ILD processes, the initial step height refers to the height difference between the dielectric material deposited outside the trench and the bottom of the trench after deposition. Ideally, this height difference should be completely eliminated after CMP treatment, making the entire surface flat. However, in reality, a certain height difference still exists after polishing, which is called the "residual step height." The higher the residual step height, the worse the planarization effect of CMP. A high residual step height can lead to problems such as focusing difficulties, uneven metal layer coverage, and increased resistance in subsequent photolithography processes, ultimately affecting device yield and performance.

[0040] In view of this, this specification provides a chemical mechanical polishing (CMP) composition and a polishing method thereof for polishing silicon oxide substrates. The abrasive grains in this CMP composition are a mixture of needle-shaped cerium oxide abrasive grains and zirconia abrasive grains, which are different from needle-shaped cerium oxide abrasive grains. These mixed abrasive grains improve material removal rate compared to existing abrasive systems. Simultaneously, these mixed abrasive grains reduce the remaining step height, thereby improving the planarization performance of the CMP composition.

[0041] Firstly, this application provides a chemical mechanical polishing composition (hereinafter referred to as the composition). This composition can be used to polish silicon oxide substrates. Specifically, the composition is suitable for planarization of silicon oxide materials in interlayer dielectrics (ILDs) or shallow trench isolation structures (STIs) during semiconductor manufacturing processes. It can also be used for efficient and high-precision chemical mechanical polishing of silicon oxide surfaces in processes such as logic devices, memories (e.g., DRAM, Flash), microelectromechanical systems (MEMS), and advanced packaging. Furthermore, the composition can also be used for polishing optical devices, display substrates, and other silicon oxide materials requiring high surface quality. It is understood that the above applications are only a few of the many applications of this composition, and other applications are also within the scope of this specification.

[0042] The composition includes abrasive grains. The abrasive grains provide a mechanical abrasive action, removing minute bumps and uneven portions on the surface of the silicon oxide substrate through chemical action and physical friction, thereby planarizing the silicon oxide substrate. The weight percentage of abrasive grains in the composition is between 0.01 and 8 wt%. In some embodiments, the weight percentage of abrasive grains in the composition is between 0.1 and 5 wt%. In some embodiments, the weight percentage of abrasive grains in the composition is between 0.5 and 3 wt%. Furthermore, the weight ratio of abrasive particles in the composition can be selected from 0.01wt%-0.05wt%, 0.05wt%-0.1wt%, 0.1wt%-0.5wt%, 0.5wt%-1wt%, 1wt%-1.5wt%, 1.5wt%-2wt%, 2wt%-2.5wt%, 2.5wt%-3wt%, 3wt%-3.5wt%, 3.5wt%-4wt%, 4wt%-4.5wt%, 4.5wt%-5wt%, 5wt%-5.5wt%, 5.5wt%-6wt%, 6wt%-6.5wt%, 6.5wt%-7wt%, 7wt%-7.5wt%, and 7.5wt%-8wt%. It is understood that the above ranges of abrasive particle weight ratios can be arbitrarily combined; for example, the weight ratio of abrasive particles in the composition can range from 1.5wt% to 3.5wt%.

[0043] The abrasive particles in the composition have a zeta potential of at least 10 mV at a pH of 3-4.5. In some embodiments, the abrasive particles have a zeta potential of at least 10 mV, 15 mV, 20 mV, or 25 mV at a pH of 3-4.5. Further, the abrasive particles in the composition have a zeta potential of 10 mV to 15 mV, 15 mV to 20 mV, 20 mV to 25 mV, 25 mV to 30 mV, 30 mV to 35 mV, 35 mV to 40 mV, 40 mV to 45 mV, 45 mV to 50 mV, or 50 mV to 80 mV at a pH of 3-4.5.

[0044] In this scheme, the abrasive grains in the composition can be hybrid abrasive grains. Hybrid abrasive grains can combine the advantages of different abrasive grains, such as increasing the polishing rate while maintaining good surface quality, and exhibit better adaptability and flexibility when processing multilayer or composite materials. They are suitable for polishing complex structures or multi-material systems, such as redistribution layers in advanced packaging technologies or the fabrication of microelectromechanical systems (MEMS) and integrated circuits (ICs).

[0045] In the case of a mixed abrasive grain, the abrasive grain includes a first abrasive grain and a second abrasive grain. The first abrasive grain is a needle-shaped cerium oxide abrasive grain. The second abrasive grain can be any suitable abrasive grain different from the first abrasive grain, such as silicon oxide abrasive grains or cerium oxide abrasive grains. In some embodiments, the second abrasive grain is a cerium oxide abrasive grain, and the second abrasive grain is different from the first abrasive grain. That is, the second abrasive grain is a cerium oxide abrasive grain other than the needle-shaped cerium oxide abrasive grain. When needle-shaped cerium oxide abrasive grains (the first abrasive grain) are used in combination with other forms of cerium oxide abrasive grains (the second abrasive grain), the two can work synergistically during the grinding process. Needle-shaped cerium oxide abrasive grains have high surface activity and directional grinding ability, which is beneficial for improving material removal rate. Other forms of cerium oxide abrasive grains help to disperse pressure, reduce surface scratches, and improve surface flatness. A proper ratio of the two can achieve a smoother and flatter surface quality while improving the removal efficiency of silicon oxide substrates.

[0046] In this invention, the first and second abrasive particles are preferably colloidal cerium oxide, i.e., nano- or micron-sized cerium oxide particles directly generated in the liquid phase by wet chemical synthesis. These particles are typically formed in aqueous solution from soluble cerium salts (such as cerium nitrate, cerium sulfate, or cerium chloride) through processes such as precipitation, hydrolysis, sol-gel, or hydrothermal / solvothermal reactions to create a stable colloidal dispersion system. The product can then be washed, concentrated, or spray-dried to obtain a wet cake or slurry.

[0047] The colloidal cerium oxide described herein differs from calcined cerium oxide. Calcined cerium oxide is typically prepared through high-temperature heat treatment (such as calcination, thermal decomposition, or solid-state reaction). Specifically, this involves drying a cerium-containing precursor (such as cerium nitrate, cerium carbonate, or cerium oxalate) and then calcining it at temperatures above 600°C in air or an inert atmosphere to remove volatile components and complete the crystal phase transformation, ultimately yielding a highly crystalline but severely agglomerated cerium oxide powder. This type of calcination process often results in severe particle sintering, reduced specific surface area, poor dispersibility, and difficulty in precisely controlling morphology and crystal face exposure.

[0048] In contrast, cerium oxide synthesized by colloidal method has advantages such as narrow particle size distribution, controllable morphology, abundant surface hydroxyl groups, and good dispersibility. It is especially suitable for fields such as chemical mechanical polishing (CMP) because it can form a stable slurry in aqueous media, achieving efficient and uniform material removal and surface smoothing.

[0049] It should be noted that, in some embodiments, the colloidal cerium oxide may undergo further low-temperature or medium-temperature calcination (e.g., 300-600°C) after wet synthesis to moderately improve crystallinity or adjust surface chemical state, while avoiding severe agglomeration or excessive grain growth caused by high temperatures. This type of "post-calcined colloidal ceria" still belongs to an extension of the colloidal synthesis pathway, and its structural characteristics (such as retained nanostructures, lower defect density, and specific crystal orientations) are significantly different from those of bulk cerium oxide obtained by traditional direct high-temperature calcination.

[0050] in, Figure 2 A scanning electron microscope image of needle-shaped cerium oxide abrasive grains provided according to an embodiment of this specification is shown. Figure 2 As shown, needle-shaped cerium oxide abrasive grains refer to cerium oxide particles with an aspect ratio significantly greater than 1, i.e., cerium oxide particles whose length is significantly greater than their width. Needle-shaped cerium oxide abrasive grains have an elongated shape; for example, they can exhibit irregularly extended structures such as slender rods, fibers, columns, or needle-like shapes. In some embodiments, the cross-section of the needle-shaped cerium oxide abrasive grains can be circular, elliptical, or polygonal. Furthermore, the axial direction of the needle-shaped cerium oxide abrasive grains is not limited to an ideal straight shape and may exhibit slight curvature or wavy shape due to manufacturing processes or other factors.

[0051] It should be noted that the needle-shaped cerium oxide abrasive grains may contain impurities. These impurities originate from the raw materials or processes used to prepare the abrasive grains and can be considered as not being part of the abrasive grain mixture; that is, these impurities are not added to the composition as a single component. This means that the impurities are not added in actual mass. The actual mass of the present invention is less than 30 ppm, further less than 20 ppm, further less than 10 ppm, and further less than 1 ppm. Here, ppm refers to weight ppm. It should be noted that the needle-shaped cerium oxide abrasive grains in this composition are preferably free of impurities. For ease of illustration, the following description will use needle-shaped cerium oxide abrasive grains comprising 100 wt% (by weight) and free of impurities.

[0052] Needle-shaped cerium oxide abrasive grains can be sol-gel cerium oxide abrasive grains, that is, cerium oxide abrasive grains prepared by hydrolysis or sol-gel methods. Among them, sol-gel cerium oxide abrasive grains can be obtained by wet processes, such as precipitation (e.g., precipitation synthesis of cerium oxide), hydrolysis-condensation reaction, or hydrothermal methods.

[0053] The average length of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, is 100 nm–5000 nm. In some embodiments, the average length of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, is 500 nm–3000 nm. Further, the average length of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, is 100 nm–200 nm, 200 nm–300 nm, 300 nm–400 nm, 400 nm–500 nm, 500 nm–600 nm, 600 nm–700 nm, 700 nm–800 nm, 800 nm–900 nm, 900 nm–1000 nm, 1000 nm–1100 nm, 1100 nm–1200 nm, 1200 nm–1300 nm. 00nm, 1300nm-1400nm, 1400nm-1500nm, 1500nm-1600nm, 1600nm-1700nm, 1700nm-1800nm, 1800nm-1900n m, 1900nm-2000nm, 2000nm-2100nm, 2100nm-2200nm, 2200nm-2300nm, 2300nm-2400nm, 2400nm-2500nm, 2 500nm-2600nm, 2600nm-2700nm, 2700nm-2800nm, 2800nm-2900nm, 2900nm-3000nm, 3000nm-3100nm, 3100 nm-3200nm, 3200nm-3300nm, 3300nm-3400nm, 3400nm-3500nm, 3500nm-3600nm, 3600nm-3700nm, 3700nm- The average length ranges of the needle-shaped cerium oxide abrasive particles are 3800nm, 3800nm-3900nm, 3900nm-4000nm, 4000nm-4100nm, 4100nm-4200nm, 4200nm-4300nm, 4300nm-4400nm, 4400nm-4500nm, 4500nm-4600nm, 4600nm-4700nm, 4700nm-4800nm, 4800nm-4900nm, and 4900nm-5000nm. It is understood that the average length ranges of the needle-shaped cerium oxide abrasive particles mentioned above can be arbitrarily combined. For example, the average length of needle-shaped cerium oxide abrasive particles measured by scanning electron microscopy is 400nm-800nm, 1000nm-1400nm, etc. All technical parameters based on scanning electron microscopy (SEM) in this application are based on the analysis of at least 1000 particles. Measurements can be performed using any SEM microscope suitable for the field and with appropriate resolution.

[0054] The average width of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, is 10 nm–300 nm. In some embodiments, the average width of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, is 50 nm–250 nm. Further, the average width of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, is 10 nm–20 nm, 20 nm–30 nm, 30 nm–40 nm, 40 nm–50 nm, 50 nm–60 nm, 60 nm–70 nm, 70 nm–80 nm, 80 nm–90 nm, 90 nm–100 nm, 100 nm–110 nm, 110 nm–120 nm, 120 nm–130 nm, 130 nm–140 nm, 140 nm–150 nm. The average width ranges of the needle-shaped cerium oxide abrasive particles, measured by scanning electron microscopy, are 150nm-160nm, 160nm-170nm, 170nm-180nm, 180nm-190nm, 190nm-200nm, 200nm-210nm, 210nm-220nm, 220nm-230nm, 230nm-240nm, 240nm-250nm, 250nm-260nm, 260nm-270nm, 270nm-280nm, 280nm-290nm, and 290nm-300nm. It is understandable that these average width ranges of needle-shaped cerium oxide abrasive particles, as measured by scanning electron microscopy, can be arbitrarily combined. For example, the average width of needle-shaped cerium oxide abrasive particles measured by scanning electron microscopy may be 30nm-90nm, 130nm-160nm, etc.

[0055] In some embodiments, the needle-shaped cerium oxide abrasive grains have an aspect ratio of 4 to 40. This range of aspect ratios is designed to balance the mechanical strength, dispersion stability, and grinding efficiency of the cerium oxide abrasive grains. Needle-shaped cerium oxide abrasive grains with different aspect ratios are suitable for different applications, as shown in Table 1.

[0056] In some embodiments, the aspect ratio of the needle-shaped cerium oxide abrasive grains is between 4 and 8. In this case, the needle-shaped cerium oxide abrasive grains have a short rod-like morphology, exhibiting excellent colloidal dispersion stability, which is beneficial for forming a uniform suspension system in the polishing slurry and is less prone to surface scratches. However, their small contact area and weak stress concentration effect result in limited cutting ability and low material removal rate, making them suitable for fine polishing stages where high surface roughness is required but the material removal amount is small.

[0057] In some embodiments, the aspect ratio of the needle-shaped cerium oxide abrasive grains is between 8 and 20. In this case, the needle-shaped cerium oxide abrasive grains possess a significantly anisotropic structure, enabling them to achieve a certain degree of directional alignment in a fluid shear field, thereby optimizing the contact mode with the workpiece surface. At this scale, the needle-shaped cerium oxide abrasive grains combine good mechanical strength with moderate elastic deformation capability, achieving a uniform contact stress distribution, effectively improving material removal efficiency, while avoiding surface scratches and subsurface damage. This makes them suitable for scenarios requiring both surface quality and material removal rate, such as chemical mechanical polishing (CMP) processes for precision optical glass, display substrates, and semiconductor wafers.

[0058] In some embodiments, the aspect ratio of the needle-shaped cerium oxide abrasive grains is between 20 and 40. In this case, the needle-shaped cerium oxide abrasive grains tend to be elongated and needle-like, theoretically providing higher local stress and stronger micro-cutting action. However, as the aspect ratio increases, its bending strength decreases significantly, and its brittleness increases, making it prone to fracture or cleavage in high-shear polishing environments, generating nanoscale fragments. These fragments may cause random scratches, particle embedding, or localized over-grinding, thus reducing surface quality consistency and increasing the difficulty of subsequent cleaning. Therefore, this range is suitable for specific high-removal-rate applications.

[0059] Table 1

[0060]

[0061] In some embodiments, the needle-shaped cerium oxide abrasive particles carry a negative charge in the composition. The charge refers to the zeta potential, which can be measured, for example, by a Mastersizer S (Malvern Instruments). As known to those skilled in the art, the zeta potential is the potential at the interface between the moving fluid within the composition and the fluid-stabilized layer attached to the abrasive particles dispersed in the composition. A higher absolute value of the zeta potential results in stronger electrostatic repulsion between particles, thereby increasing the stability of the particle dispersion in the composition. The needle-shaped cerium oxide abrasive particles have a negative zeta potential in the composition at a pH of 7.5 to 9.5. Furthermore, the needle-shaped cerium oxide abrasive particles have a zeta potential of -5 mV to -90 mV in the composition at a pH of 7.5 to 9.5. For example, needle-shaped cerium oxide abrasive grains in the composition have zeta potentials of -5mV to -15mV, -15mV to -30mV, -30mV to -50mV, -50mV to -70mV, and -70mV to -90mV at pH 7.5 to 9.5.

[0062] In some embodiments, the needle-shaped cerium oxide abrasive particles are positively charged in the composition. A higher zeta potential results in stronger electrostatic repulsion between particles, thereby increasing the stability of the particle dispersion in the composition. The needle-shaped cerium oxide abrasive particles in the composition have a zeta potential of 10 mV to 90 mV at a pH of 3 to 4.5. For example, the needle-shaped cerium oxide abrasive particles in the composition have zeta potentials of 10 mV to 20 mV, 20 mV to 30 mV, 30 mV to 40 mV, 40 mV to 50 mV, 50 mV to 60 mV, 60 mV to 70 mV, 70 mV to 80 mV, and 80 mV to 90 mV at a pH of 3 to 4.5.

[0063] The second abrasive grain may include, but is not limited to, spherical cerium oxide abrasive grains, polyhedral cerium oxide abrasive grains, plate-like cerium oxide abrasive grains, blocky cerium oxide abrasive grains, or polycrystalline agglomerated cerium oxide abrasive grains. The polyhedral cerium oxide abrasive grain may be at least one of cubic cerium oxide abrasive grains, octahedral cerium oxide abrasive grains, or chamfered octahedral cerium oxide abrasive grains.

[0064] Figure 1 Visible Raman spectra of chamfered octahedral cerium oxide abrasive grains, needle-shaped cerium oxide abrasive grains A, and needle-shaped cerium oxide abrasive grains B provided according to embodiments of this specification are shown at an excitation wavelength of 532 nm. Figure 1 As shown, the second abrasive grain exhibits a narrow F2g peak as assessed by visible Raman spectroscopy. Visible Raman spectra can be obtained at 25°C using an FRS27 Raman spectrometer (Bruker Corp.) with a 532 nm laser on the dry powder of the cerium oxide abrasive grain (the second abrasive grain). As those skilled in the art know, the F2g peak appears at 464 cm⁻¹. -1 This corresponds to the Ce-O vibration. The Raman spectrum should be baseline corrected and normalized to the intensity of the F2g peak. The Full Width at Half Maximum (FWHM) can be used to describe the width of the F2g peak at half its peak height. FWHM is the wavelength difference at half the maximum intensity of the visible Raman spectrum measured at 532 nm from the F2g peak intensity.

[0065] In some embodiments, the needle-shaped cerium oxide abrasive grains have a Free Wavelength (FWHM) range of 10 cm⁻¹ as measured by Raman spectroscopy at a wavelength of 532 nm. -1 -100cm -1 The F2g peak. In some embodiments, the needle-shaped cerium oxide abrasive grains have an FWHM range of 20 cm⁻¹ measured by Raman spectroscopy at a wavelength of 532 nm. -1 -80cm -1 The F2g peak was observed. Furthermore, the needle-shaped cerium oxide abrasive grains exhibited a Raman spectroscopy FWHM range of 10 cm⁻¹ measured at 532 nm. -1 -15cm -1 15cm-1 -20cm -1 20cm -1 -25cm -1 25cm -1 -30cm -1 30cm -1 -35cm -1 35cm -1 -40cm -1 40cm -1 -45cm -1 45cm -1 -50cm -1 50cm -1 -55cm -1 55cm -1 -55cm -1 55cm -1 -60cm -1 60cm -1 -65cm -1 65cm -1 -70cm -1 70cm -1 -75cm -1 75cm -1 -80cm -1 80cm -1 -85cm -1 85cm -1 -90cm -1 90cm -1 -95cm -1 95cm -1 -100cm -1 The F2g peak.

[0066] In some embodiments, the cerium oxide abrasive grains (second abrasive grains) have a Raman spectroscopy FWHM range of 5 cm measured at a wavelength of 532 nm. -1 -42cm -1 The F2g peak. In some embodiments, the cerium oxide abrasive grains (second abrasive grains) have an FWHM range of 10 cm⁻¹ measured by Raman spectroscopy at a wavelength of 532 nm. -1 -28cm -1 The F2g peak was observed. Furthermore, the cerium oxide abrasive grains (the second abrasive grains) exhibited a Raman spectroscopy FWHM range of 5 cm⁻¹ measured at 532 nm. -1 -10cm -1 10cm -1 -15cm -1 15cm -1 -20cm -1 20cm-1 -25cm -1 25cm -1 -30cm -1 30cm -1 -35cm -1 35cm -1 -40cm -1 40cm -1 -42cm -1 The F2g peak.

[0067] It should be noted that, compared to the second abrasive grain (cerium oxide abrasive grain), the first abrasive grain (acicular cerium oxide abrasive grain) exhibits a broad F2g peak in visible Raman spectroscopy evaluation. That is, the FWHM of the first abrasive grain (acicular cerium oxide abrasive grain) measured at 532 nm should be significantly greater than that of the second abrasive grain (cerium oxide abrasive grain) measured at 532 nm. For example, the FWHM of the first abrasive grain (acicular cerium oxide abrasive grain) measured at 532 nm should be 1-5 times that of the second abrasive grain (cerium oxide abrasive grain) measured at 532 nm. For instance, the FWHM of the first abrasive grain (acicular cerium oxide abrasive grain) measured at 532 nm could be 1, 1.1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 times greater than that of the second abrasive grain (cerium oxide abrasive grain) measured at 532 nm.

[0068] The F2g vibrational mode of cerium oxide abrasive particles exhibits characteristic peak broadening behavior in the visible Raman spectrum excited at 532 nm. To evaluate the degree of peak wing broadening, the full width at one third of the maximum (FWTM) is used as a characterization parameter, defined as the wavenumber difference (in cm⁻¹) between two points when the Raman intensity of the F2g peak reaches one-third of its maximum value.

[0069] In some embodiments, the needle-shaped cerium oxide abrasive grains have an FWTM of 30 cm⁻¹ as measured by Raman spectroscopy at a wavelength of 532 nm. -1 Up to 200cm -1 The F2g peak. In some embodiments, the needle-shaped cerium oxide abrasive grains have an FWTM of 40 cm⁻¹ as measured by Raman spectroscopy at a wavelength of 532 nm. -1 Up to 130cm -1 The F2g peak was observed. Furthermore, the needle-shaped cerium oxide abrasive grains exhibited an FWTM of 30 cm⁻¹ measured by Raman spectroscopy at 532 nm wavelength. -1 -40cm -1 40cm -1 -50cm -1 50cm -1 -60cm-1 60cm -1 -70cm -1 70cm -1 -80cm -1 80cm -1 -90cm -1 90cm -1 -100cm -1 100cm -1 -110cm -1 110cm -1 -120cm -1 120cm -1 -130cm -1 130cm -1 -140cm -1 140cm -1 -150cm -1 150cm -1 -160cm -1 160cm -1 -170cm -1 170cm -1 -180cm -1 180cm -1 -190cm -1 190cm -1 -200cm -1 The F2g peak.

[0070] In some embodiments, the second abrasive grain (cerium oxide abrasive grain) has an FWTM of 10 cm⁻¹ as measured by Raman spectroscopy at a wavelength of 532 nm. -1 Up to 60cm -1 The F2g peak. In some embodiments, the second abrasive grain (cerium oxide abrasive grain) has an FWTM of 15 cm⁻¹ as measured by Raman spectroscopy at a wavelength of 532 nm. -1 Up to 45cm -1 The F2g peak was observed. Furthermore, the second abrasive grain (cerium oxide abrasive grain) exhibited an FWTM of 15 cm⁻¹ as measured by Raman spectroscopy at a wavelength of 532 nm. -1 -20cm -1 20cm -1 -25cm -1 25cm -1 -30cm -1 30cm -1 -35cm -1 35cm -1 -40cm -1 40cm -1 -45cm -1 45cm-1 -50cm -1 50cm -1 -55cm -1 55cm -1 -60cm -1 The F2g peak.

[0071] It should be noted that, compared to the second abrasive grain (cerium oxide abrasive grain), the first abrasive grain (acicular cerium oxide abrasive grain) exhibits a broad F2g peak in visible Raman spectroscopy evaluation. That is, the FWTM measured at 532 nm by the first abrasive grain (acicular cerium oxide abrasive grain) should be significantly larger than that measured by the second abrasive grain (cerium oxide abrasive grain) at 532 nm. For example, the FWTM measured by the first abrasive grain (acicular cerium oxide abrasive grain) at 532 nm should be 1-5 times larger than that measured by the second abrasive grain (cerium oxide abrasive grain) at 532 nm. For instance, the FWTM measured by the first abrasive grain (acicular cerium oxide abrasive grain) at 532 nm could be 1, 1.1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 times larger than that measured by the second abrasive grain (cerium oxide abrasive grain) at 532 nm.

[0072] The first abrasive grain (needle-shaped cerium oxide abrasive grain) and the second abrasive grain (cerium oxide abrasive grain) having the above-mentioned preferred full width at half maximum and full width at 1 / 3 of the maximum peak value can be obtained by controlling appropriate synthesis conditions, such as temperature, pressure and time, which will not be elaborated here.

[0073] Figure 3 A scanning electron microscope image of uncalcined chamfered octahedral cerium oxide abrasive grains (purchased) provided according to an embodiment of this specification is shown; Figure 4 A scanning electron microscope image of uncalcined chamfered octahedral cerium oxide abrasive grains (prepared) according to an embodiment of this specification is shown; Figure 5 A scanning electron microscope image of calcined chamfered octahedral cerium oxide abrasive grains provided according to an embodiment of this specification is shown. Figures 3-5As shown, the second abrasive in this solution can be a chamfered octahedral cerium oxide abrasive. The term "chamfered octahedron" in this application refers to a polyhedron, specifically a polyhedron with 8 hexagonal faces and 6 square faces. Within the scope of this application, "chamfered octahedral cerium oxide" is not limited to an ideal truncated octahedral shape, but also includes octahedrons whose morphology changes due to manufacturing processes or other factors. For example, chamfered octahedral cerium oxide abrasives may have more or fewer than 8 hexagonal faces, and / or more or fewer than 6 square faces. The hexagonal or square faces may exhibit shape deviations (such as imperfect symmetry, irregular side lengths, or slight curvature). In some embodiments, the surface of the chamfered octahedral cerium oxide abrasive may exhibit a certain degree of unevenness or deformation. Studies have found that the chamfered octahedral morphology can improve the surface morphology of the ILD structure after polishing, while still exhibiting a high silicon oxide removal rate.

[0074] It should be noted that the chamfered octahedral cerium oxide abrasive grains may contain impurities. These impurities originate from the raw materials or processes used to prepare the abrasive grains and can be considered as not being part of the abrasive grain mixture; that is, these impurities are not added to the composition as a single component. This means that the impurities are not added in actual mass. The actual mass of the present invention is less than 30 ppm, further less than 20 ppm, further less than 10 ppm, and further less than 1 ppm. Here, ppm refers to weight ppm. It should be noted that the chamfered octahedral cerium oxide abrasive grains in this composition are preferably chamfered octahedral cerium oxide abrasive grains without impurities. For ease of illustration, the following description will use 100 wt% chamfered octahedral cerium oxide abrasive grains without impurities.

[0075] Chamfered octahedral cerium oxide abrasive grains can be sol-gel cerium oxide abrasive grains, i.e., cerium oxide abrasive grains prepared by hydrolysis or sol-gel methods. Sol-gel cerium oxide abrasive grains can be obtained through wet processes, such as precipitation (e.g., precipitation synthesis of cerium oxide), hydrolysis-condensation reactions, or hydrothermal methods. See also Figure 3 In some embodiments, the chamfered octahedral cerium oxide abrasive grains can be uncalcined chamfered octahedral cerium oxide abrasive grains (purchased). These chamfered octahedral cerium oxide abrasive grains are purchased directly from the market and have monodisperse distribution characteristics, that is, uniform particle size and narrow distribution range.

[0076] See Figure 4In some embodiments, the chamfered octahedral cerium oxide abrasive grains can be uncalcined chamfered octahedral cerium oxide abrasive grains (prepared). In this application, uncalcined chamfered octahedral cerium oxide abrasive grains refer to cerium oxide sol particles that have not undergone calcination treatment, i.e., dispersed cerium oxide nanoparticles prepared directly by sol-gel method, hydrolysis method, precipitation method or similar wet process. The combined use of uncalcined chamfered octahedral cerium oxide abrasive grains and needle-shaped cerium oxide abrasive grains can combine the advantages of both. Uncalcined abrasive grains have high surface activity and good dispersibility, providing a fine and uniform polishing effect and reducing surface defects; while needle-shaped abrasive grains help improve material removal rate. The synergistic effect of the two can achieve efficient and high-quality surface smoothing. It should be noted that the uncalcined chamfered octahedral cerium oxide abrasive grains here are self-prepared and have polydispersity.

[0077] See Figure 5 In some embodiments, the chamfered octahedral cerium oxide abrasive grains can be calcined chamfered octahedral cerium oxide abrasive grains (prepared). Calcined chamfered octahedral cerium oxide abrasive grains (post-calcined colloidal ceria) refer to the above-mentioned ( Figure 4 Colloidal chamfered octahedral cerium oxide abrasive grains are calcined cerium oxide particles. This involves first preparing chamfered octahedral cerium oxide abrasive grains, then calcining them at high temperatures to alter their crystallinity, surface chemical properties, particle morphology, or other physicochemical properties. The calcined chamfered octahedral cerium oxide abrasive grains, due to the high-temperature treatment, possess higher hardness and crystallinity, further improving removal efficiency, enhancing stability and durability during the grinding process, and improving the final surface smoothness.

[0078] The average particle size of the chamfered octahedral cerium oxide abrasive particles, as measured by scanning electron microscopy, is 10 nm–200 nm. In some embodiments, the average particle size of the chamfered octahedral cerium oxide abrasive particles, as measured by scanning electron microscopy, is 20 nm–100 nm. Furthermore, the average particle size of the chamfered octahedral cerium oxide abrasive particles, measured by scanning electron microscopy, is 10nm-20nm, 20nm-30nm, 30nm-40nm, 40nm-50nm, 50nm-60nm, 60nm-70nm, 70nm-80nm, 80nm-90nm, 80nm-90nm, 90nm-100nm, 100nm-110nm, 110nm-120nm, 120nm-130nm, 130nm-140nm, 140nm-150nm, 150nm-160nm, 160nm-170nm, 170nm-180nm, 180nm-190nm, and 190nm-200nm. The average particle size refers to the arithmetic mean of the maximum distance between two points on the particle boundary.

[0079] The particle size distribution of the chamfered octahedral cerium oxide abrasive grains can be described using the coefficient of variation (CV) of the average particle size measured by scanning electron microscopy. Further, the coefficient of variation of the average particle size CV = (σ / μ) × 100%, where σ is the standard deviation of the average particle size and μ is the average particle size measured by scanning electron microscopy. In this embodiment, the coefficient of variation of the average particle size of the chamfered octahedral cerium oxide abrasive grains measured by scanning electron microscopy is greater than 30%. Further, the coefficient of variation of the average particle size of the chamfered octahedral cerium oxide abrasive grains measured by scanning electron microscopy is greater than 31%, 32%, 33%, 34%, or 35%. It should be noted that the standard deviation and coefficient of variation of the average particle size are determined by SEM. Studies show that the coefficient of variation of the average particle size of the present invention can improve the silica removal rate.

[0080] The particle size distribution of chamfered octahedral cerium oxide abrasive grains can be described using the polydispersity index (PDI) measured by scanning electron microscopy. Chamfered octahedral cerium oxide abrasive grains exhibit a non-monodispersive particle size distribution. Further, the polydispersity index PDI = σ 2 / μ 2 Where σ is the standard deviation of the average particle size, and μ is the average particle size measured by scanning electron microscopy (SEM). It should be noted that the PDI measured by SEM differs fundamentally from that measured by dynamic light scattering (DLS) or laser diffraction. In this embodiment, the polydispersity index (PDI) of the chamfered octahedral cerium oxide abrasive particles, measured by SEM, is at least 0.1. Further, the PDI of the chamfered octahedral cerium oxide abrasive particles, measured by SEM, is at least 0.105, 0.110, 0.115, or 0.120. It should be noted that the standard deviation of the average particle size and the PDI are determined by SEM. Studies have shown that the PDI of this invention can improve the removal rate of silicon oxide substrates.

[0081] During the polishing process, the particle size of the chamfered octahedral cerium oxide abrasive grains affects the material removal rate of the substrate. Larger-diameter chamfered octahedral cerium oxide abrasive grains can enhance the material removal rate, while smaller-diameter grains can fill the gaps between the larger grains, thus preventing surface defects in the substrate material caused by the large-diameter grains. In this embodiment, at least 0.5% of the chamfered octahedral cerium oxide abrasive grains have a particle size greater than twice the average particle size as measured by scanning electron microscopy. Further, at least 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, or 1.7% of the chamfered octahedral cerium oxide abrasive grains have a particle size greater than twice the average particle size as measured by scanning electron microscopy.

[0082] In this scheme, the ratio of the cumulative volume of abrasive grains having an average particle size more than twice that measured by scanning electron microscopy to the cumulative volume of abrasive grains with a particle size less than that measured by scanning electron microscopy in the chamfered octahedral cerium oxide abrasive is at least 0.1. Further, the ratio of the cumulative volume of abrasive grains having an average particle size more than twice that measured by scanning electron microscopy to the cumulative volume of abrasive grains with a particle size less than that measured by scanning electron microscopy in the chamfered octahedral cerium oxide abrasive is at least 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.46, or 0.50. Studies have found that the aforementioned ratios can improve the removal rate of silicon oxide substrates.

[0083] In some embodiments, the chamfered octahedral cerium oxide abrasive grains in the composition carry a negative charge. The charge refers to the zeta potential, which can be measured, for example, by a Mastersizer S (Malvern Instruments). As known to those skilled in the art, the zeta potential is the potential at the interface between the moving fluid within the composition and the fluid-stabilized layer attached to the abrasive grains dispersed in the composition. A higher absolute value of the zeta potential results in stronger electrostatic repulsion between particles, thereby increasing the stability of the particle dispersion in the composition. The chamfered octahedral cerium oxide abrasive grains in the composition have a negative zeta potential at pH 7.5 to 9.5. Furthermore, the chamfered octahedral cerium oxide abrasive grains in the composition have a zeta potential of -5 mV to -90 mV at pH 7.5 to 9.5. For example, chamfered octahedral cerium oxide abrasive grains in the composition have zeta potentials of -5mV to -15mV, -15mV to -30mV, -30mV to -50mV, -50mV to -70mV, and -70mV to -90mV at pH 7.5 to 9.5.

[0084] In some embodiments, the chamfered octahedral cerium oxide abrasive particles are positively charged in the composition. A higher zeta potential results in stronger electrostatic repulsion between particles, thereby increasing the stability of the particle dispersion in the composition. The chamfered octahedral cerium oxide abrasive particles in the composition have a zeta potential of 10 mV to 90 mV at a pH of 3 to 4.5. For example, the chamfered octahedral cerium oxide abrasive particles in the composition have zeta potentials of 10 mV to 20 mV, 20 mV to 30 mV, 30 mV to 40 mV, 40 mV to 50 mV, 50 mV to 60 mV, 60 mV to 70 mV, 70 mV to 80 mV, and 80 mV to 90 mV at a pH of 3 to 4.5.

[0085] The weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains ranges from 9:1 to 1:9. For example, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains is 9:1, 8:2, 7:3, 6:4, 1:1, 4:6, 3:7, 2:8, and 1:9. Correspondingly, the proportion of the first abrasive grain in the mixed abrasive grains is between 10% and 90%. For example, the proportion of the first abrasive grain in the mixed abrasive grains is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%. The proportion of the second abrasive grain in the mixed abrasive grains is between 10% and 90%. For example, the proportion of the second abrasive grain in the mixed abrasive grains is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%.

[0086] In some embodiments, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains ranges from 9:1 to 3:1. For example, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains is 9:1, 8:2, 7:3, 6:4, or 3:1. Accordingly, the proportion of the first abrasive grain in the mixed abrasive grains is between 75% and 90%. For example, the proportion of the first abrasive grain in the mixed abrasive grains is 75%, 80%, or 90%. The proportion of the second abrasive grain in the mixed abrasive grains is between 10% and 25%. For example, the proportion of the second abrasive grain in the mixed abrasive grains is 10%, 20%, or 25%. In this case, the proportion of needle-shaped cerium oxide abrasive grains is relatively high. Polishing with mixed abrasive grains added in this proportion results in a high material removal rate. In this case, the composition is suitable for scenarios requiring rapid finishing or rough polishing.

[0087] In some embodiments, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains ranges from 3:1 to 1:3. For example, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains is 3:1, 1:1, or 1:3. Accordingly, the proportion of the first abrasive grain in the mixed abrasive grains is between 25% and 75%. For example, the proportion of the first abrasive grain in the mixed abrasive grains is 25%, 35%, 45%, 55%, 65%, or 75%. The proportion of the second abrasive grain in the mixed abrasive grains is between 25% and 75%. For example, the proportion of the second abrasive grain in the mixed abrasive grains is 25%, 35%, 45%, 55%, 65%, or 75%. In this case, the proportions of needle-shaped cerium oxide abrasive grains and chamfered octahedral cerium oxide abrasive grains are roughly equal. The synergistic effect of the two abrasive grains is significant. Polishing using mixed abrasive grains with this proportion results in a high material removal rate and good surface smoothness. In this case, the composition is suitable for scenarios that balance removal efficiency and surface quality.

[0088] In some embodiments, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains ranges from 1:3 to 1:9. For example, the weight ratio of the first abrasive grain to the second abrasive grain in the mixed abrasive grains is 1:3, 4:6, 3:7, 2:8, or 1:9. Accordingly, the proportion of the first abrasive grain in the mixed abrasive grains is between 10% and 25%. For example, the proportion of the first abrasive grain in the mixed abrasive grains is 10%, 20%, or 25%. The proportion of the second abrasive grain in the mixed abrasive grains is between 75% and 90%. For example, the proportion of the second abrasive grain in the mixed abrasive grains is 75%, 80%, or 90%. The abrasive action of the composition is more uniform and gentle. Polishing with mixed abrasive grains added in this proportion results in a better surface smoothness. In this case, the composition is suitable for applications requiring precision polishing and high surface quality.

[0089] In some embodiments, the mixed abrasive particles of the first and second abrasive particles have a negative zeta potential at a pH of 7.5 to 9.5. More specifically, the mixed abrasive particles in the composition have a zeta potential of -5 mV to -90 mV at a pH of 7.5 to 9.5. For example, the mixed abrasive particles in the composition have zeta potentials of -5 mV to -15 mV, -15 mV to -30 mV, -30 mV to -50 mV, -50 mV to -70 mV, and -70 mV to -90 mV at a pH of 7.5 to 9.5.

[0090] In some embodiments, the mixed abrasive particles of the first and second abrasive particles have a zeta potential of 10 mV to 90 mV at a pH of 3 to 4.5. For example, the mixed abrasive particles in the composition have zeta potentials of 10 mV to 20 mV, 20 mV to 30 mV, 30 mV to 40 mV, 40 mV to 50 mV, 50 mV to 60 mV, 60 mV to 70 mV, 70 mV to 80 mV, and 80 mV to 90 mV at a pH of 3 to 4.5.

[0091] The composition includes a liquid carrier. The liquid carrier can contain other components of the composition besides the liquid carrier itself, suspending these components in the liquid carrier and allowing them to contact the substrate for polishing. The liquid carrier can be an aqueous carrier, or any component suitable for suspending abrasive particles and chemical additives. The liquid carrier can be one of water, ethers (such as dioxane and tetrahydrofuran), and alcohols (such as methanol and ethanol), or a combination of water, ethers (such as dioxane and tetrahydrofuran), and alcohols (such as methanol and ethanol). When the liquid carrier is a combination of multiple components, the liquid carrier contains at least 50 wt% water, for example, the aqueous carrier contains 50 wt%, 70 wt%, 90 wt%, 95 wt%, or 99 wt% water. The liquid carrier is water. Further, the water is deionized water.

[0092] The composition also includes one or more polishing aids. The polishing aids are dissolved in a liquid carrier. The polishing aids can interact with abrasive particles and / or with the substrate and / or with the polishing pad during CMP processing. This interaction can be based on, for example, hydrogen bonds, van der Waals forces, electrostatic forces, etc. The polishing aids can be any component suitable for use as, for example, a removal rate promoter, a polishing rate inhibitor, a surfactant, a thickener, a modifier, a complexing agent, a chelating agent, a biocide, a dispersant, an oxidizing agent, a film-forming agent, an etching inhibitor, a catalyst, a terminating compound, a dissolution inhibitor, or a combination thereof.

[0093] Polishing aids include sugar alcohols. In the CMP process, sugar alcohols, as polishing aids, improve the contact between abrasive grains and the silicon oxide surface through their surface activity, enhancing lubrication and reducing surface defects. These functions work together to enable the CMP process using cerium oxide and zirconium oxide mixed abrasive grains to remove silicon oxide material more efficiently, thereby improving the material removal rate of silicon oxide substrates.

[0094] Sugar alcohols include at least one of hexapeptides, pentapeptides, tetrapeptides, or tripeptides. Hexapeptides include at least one of sorbitol, mannitol, idutol, galactitol, aritol, atetol, L-fucoitol, allotol, or a cyclic hexol (such as inositol). Pentapeptides include at least one of xylitol, threitol, arabinitol, or ribitol. Tetrapeptides include at least one of erythritol or threitol. Tripeptides include glycerol.

[0095] Sugar alcohols also include at least one of disaccharide-derived sugar alcohols, cyclic sugar alcohols, neurocyclols, or anhydrous sugar alcohols. Disaccharide-derived sugar alcohols include at least one of maltitol, lactitol, isomaltitol, polysorbate, or hydrogenated starch hydrolysate. Cyclic sugar alcohols include at least one of inositol, cytosine, or skeletal inositol. Neurocyclols include at least one of quercetin. Anhydrous sugar alcohols include at least one of anhydrous erythritol or lactitin anhydride.

[0096] Polishing aids also include monocarboxylic acids. Monocarboxylic acids can enhance the removal rate of silicon oxide substrates. Monocarboxylic acids can be straight-chain monocarboxylic acids, branched monocarboxylic acids, saturated monocarboxylic acids, unsaturated monocarboxylic acids, substituted monocarboxylic acids, aromatic monocarboxylic acids, and combinations thereof. Further, monocarboxylic acids include nicotinic acid, isonicotinic acid, quinacrine, acetic acid, picolinic acid, hydroxybenzoic acid, formic acid, carbonic acid, glycolic acid, glyoxylic acid, lactic acid, glyceric acid, pyruvic acid, oxopropionic acid, hydroxypropionic acid, oxopropionic acid, glycidic acid, butyric acid, isobutyric acid, butyric acid, propionic acid, crotonic acid, isocrotonic acid, acrylic acid, methacrylic acid, vinylacetic acid, butynedic acid, hydroxybutyric acid, oxobutyric acid, valeric acid, isovaleric acid, neovaleric acid, hexanoic acid, sorbic acid, benzoic acid, salicylic acid, caprylic acid, nonanoic acid, cinnamic acid, decanoic acid, myristic acid, palmitic acid, stearic acid, and combinations thereof. In specific embodiments of this scheme, the monocarboxylic acid can be propionic acid, butyric acid, acetic acid, valeric acid, hexanoic acid, picolinic acid, or combinations thereof.

[0097] The polishing aid also includes a pH adjuster. This pH adjuster helps the composition achieve a suitable pH. The pH adjuster can be an acid or a salt thereof. The acid or its salt can be an organic acid, an inorganic acid, or a combination thereof. Organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, methylbutyric acid, hexanoic acid, dimethylbutyric acid, ethylbutyric acid, methylvaleric acid, heptanoic acid, methylhexanoic acid, octanoic acid, ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, malic acid, phthalic acid, tartaric acid, citric acid, lactic acid, diethylene glycol, furanyl carboxylic acid, tetrahydrofuranic acid, methoxyacetic acid, methoxyphenylacetic acid, phenoxyacetic acid, methanesulfonic acid, ethanesulfonic acid, sulfosuccinic acid, benzenesulfonic acid, toluenesulfonic acid, phenylphosphonic acid, hydroxyethyl diphosphonic acid, and combinations thereof. Inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, phosphoric acid, and combinations thereof.

[0098] The preferred pH adjuster is an organic acid. In a particularly preferred embodiment, the organic acid is selected from maleic acid, malic acid, tartaric acid, citric acid, acetic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, and combinations thereof.

[0099] In some embodiments, the polishing aid optionally includes a pH buffer. This pH buffer helps maintain a suitable pH in the composition. The pH buffer can be any suitable buffer. For example, the pH buffer can be a phosphate, sulfate, acetate, borate, ammonium salt, or a combination thereof.

[0100] The pH value of the composition affects the removal rate of the silicon oxide substrate during CMP processing. In some embodiments, the composition has a pH value between 3 and 5 when used. For example, the composition has a pH value between 3 and 3.5, 3.5 and 4, 4 and 4.5, and 4.5 and 5 when used. In other embodiments, the composition has a pH value between 7 and 10 when used. For example, the composition has a pH value between 7 and 7.5, 7.5 and 8, 8 and 8.5, 8.5 and 9, 9 and 9.5 and 10 when used.

[0101] The polishing aid also includes a coating agent. In embodiments where the coating agent is used with negatively charged abrasive grains, such as negatively charged chamfered octahedral cerium oxide abrasive grains or negatively charged needle-shaped cerium oxide abrasive grains, the coating agent can reversibly bind to the abrasive grain surface via hydrogen bonding and / or ionic interactions. The coating agent as used herein refers to a coating agent present in the composition in any form, whether bound to or not bound to the abrasive grain surface. Preferably, the abrasive grains are coated with a coating agent. The surface of the abrasive grains can be treated with the coating agent by any suitable method. For example, the coating agent can be dissolved in an aqueous carrier such as deionized water and then added to the abrasive grains to form a mixture. The mixture is then stirred until the components are dissolved. The mixture of coating agent and abrasive grains is then added to the composition.

[0102] The coating agent is an anionic polymer. The anionic polymer can be used in any feasible form, such as an acid, conjugate acid, conjugate base, salt (e.g., ammonium salt), or combinations thereof. The anionic polymer contains repeating monomer units. The monomer units contain functional groups selected from carboxylic acids, sulfonic acids, sulfates, phosphonic acids, phosphoric acids, and combinations thereof.

[0103] In some embodiments, the repeating monomer unit may be a repeating monomer unit containing a carboxylic acid functional group. The repeating monomer unit containing a carboxylic acid functional group includes maleic acid, acrylic acid, aspartic acid, methacrylic acid, succinic acid, terephthalic acid, itaconic acid, and combinations thereof.

[0104] In some embodiments, the repeating monomer unit may be a repeating monomer unit containing a sulfonic acid functional group. The repeating monomer unit containing a sulfonic acid functional group includes vinyl sulfonic acid, styrene sulfonic acid, vinylbenzene sulfonic acid, ethyl methacrylate, propylene sulfonic acid, 3-sulfopropyl acrylate, propyl methacrylate, propyl sulfonate, acrylamide methylpropane sulfonic acid (AMPS), ethyl acrylate, sodium styrene sulfonate, and combinations thereof.

[0105] In some embodiments, the repeating monomer unit may be a repeating monomer unit containing a phosphonic acid functional group. The repeating monomer unit containing a phosphonic acid functional group includes ammonium diethylphosphonate methacrylate, vinylphosphonic acid, vinylbenzyldimethylphosphonic acid, acrylamide phosphonic acid, vinylidene diphosphonic acid, and combinations thereof.

[0106] Anionic polymers can be homopolymers, copolymers, or combinations thereof. Anionic homopolymers include polysulfonic acid, poly(acrylamidomethylpropanesulfonic acid), polystyrene sulfonic acid, poly(vinyl sulfonic acid), poly(aspartic acid), polyacrylic acid, polymethacrylic acid, phosphonic polyacrylic acid, poly(methacrylic acid), poly(maleic acid), poly(itaconic acid), poly(maleic anhydride), anionic polyacrylamide, poly(methacrylamide), poly(methyl vinyl ether-copolymer-maleic acid), poly(methacrylamidomethylpropanesulfonic acid), poly(vinyl phosphonic acid), poly(vinyl phosphoric acid), poly(acrylamidomethylpropanesulfonic acid), poly(methacryloyloxyethanesulfonic acid), poly(acrylamidomethylpropanesulfonic acid), poly(methacryloyloxyethanesulfonic acid), and poly(methacryloyloxyethanesulfonic acid). Poly(methacrylamide propanesulfonic acid), poly(methacrylamidomethylpropanesulfonic acid), carboxymethyl inulin, polynaphthalenesulfonic acid, polyhydroxypropyl acrylate, poly(octadecyl acrylate), poly(tert-butyl acrylate), poly(tetrahydrofurfuryl methacrylate), poly(ethyl acrylate), poly(isoborneol acrylate), poly(isobutyl acrylate), poly(isodecyl acrylate), poly(isodecyl methacrylate), poly(isooctyl acrylate), poly(lauryl acrylate), poly(propyl acrylate), poly(butyl acrylate), poly(decyl acrylate), poly(hexyl acrylate), poly(octyl acrylate), poly(octyl methacrylate), polyepoxysuccinic acid, phosphonomethylated chitosan and combinations thereof.

[0107] The copolymers include poly(acrylic acid-conmaleic acid) copolymers, poly(styrene sulfonic acid-conmaleic acid), poly(acrylamide-coacrylic acid), poly(vinylphosphonic acid-coacrylic acid), poly(vinyl sulfate), acrylic acid-acrylamide-methylpropanesulfonic acid copolymers, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid (AA-AMPS) in different weight percentages as shown, and combinations thereof.

[0108] The coating agent should have a low molecular weight (MW). If the molecular weight of the coating agent is too high, it will cause abrasive grain aggregation and agglomeration, resulting in defects such as scratches on the substrate surface, and leading to abrasive grain deposition and a shortened shelf life. The coating agent has a molecular weight of 100 g / mol to 50,000 g / mol. For example, coating agents have molecular weights of 100 g / mol to 200 g / mol, 200 g / mol to 1000 g / mol, 1000 g / mol to 900 g / mol, 9000 g / mol to 15000 g / mol, 15000 g / mol to 20000 g / mol, 20000 g / mol to 30000 g / mol, and 30000 g / mol to 50000 g / mol.

[0109] When used, the composition contains a coating agent at a concentration of 0.0001 wt.% to 2.0 wt.%. For example, the composition contains a coating agent at concentrations of 0.0001 wt.% to 0.001 wt.%, 0.001 wt.% to 0.01 wt.%, 0.01 wt.% to 0.1 wt.%, 0.1 wt.% to 0.6 wt.%, 0.6 wt.% to 0.8 wt.%, 0.8 wt.% to 1 wt.%, 1 wt.% to 1.5 wt.%, and 1.5 wt.% to 2 wt.%.

[0110] In some embodiments, the polishing aid further includes amino acids. The amino acids can be at least one of protein-derived amino acids or non-protein-derived amino acids. Protein-derived amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, selenocysteine, pyrrolidone, or combinations thereof. Non-protein-derived amino acids include ornithine, citrulline, carnitine, γ-aminobutyric acid, levothyroxine, β-alanine, aminoisobutyric acid, or combinations thereof. Preferably, the amino acids are protein amino acids. In a preferred embodiment, the molecular weight of the amino acid is at most 150 g / mol, more preferably at most 140 g / mol, even more preferably at most 130 g / mol, and most preferably at most 120 g / mol.

[0111] When used, the composition contains amino acids in amounts between 0.001 wt.% and 18.3 wt.%. For example, the composition contains amino acids in amounts between 0.001 wt.% and 0.1 wt.%, 0.1 wt.% and 0.3 wt.%, 0.3 wt.% and 1 wt.%, 1 wt.% and 2.9 wt.%, 2.9 wt.% and 4.3 wt.%, 4.3 wt.% and 6.3 wt.%, 6.3 wt.% and 9.8 wt.%, 9.8 wt.% and 10.8 wt.%, and 10.8 wt.% and 18.3 wt.%.

[0112] Secondly, this application also provides a polishing method for a silicon oxide substrate. The method includes the following steps: (a) providing the above-described chemical mechanical polishing composition; (b) contacting the silicon oxide substrate with the chemical mechanical polishing composition and a polishing pad; (c) moving the polishing pad relative to the silicon oxide substrate, with the chemical mechanical polishing composition positioned therebetween; and (d) removing at least a portion of the silicon oxide substrate. The method may optionally include other steps.

[0113] The composition can be prepared using suitable techniques known to those skilled in the art. The abrasive particles and other components, as described above, can be added to the liquid carrier in any order and in suitable amounts to achieve the desired concentration. The abrasive particles and other components can be mixed and stirred in the liquid carrier. The pH value can be adjusted using the pH adjuster and pH buffer described above to obtain and maintain the desired pH. The abrasive particles and other components can be added at any time before use or during CMP treatment.

[0114] The composition can be provided as a single-part system, a two-part system, or a multi-part system. For example, as a two-part system, the first part may include abrasive grains, and the second part may include one or more other components. The first and second parts can be mixed at any time before or during the CMP treatment.

[0115] The following are specific embodiments of the compositions designed according to the above disclosure. It should be understood that the following embodiments are merely illustrative of the compositions and polishing methods disclosed above, and the specific implementation methods and parameters used are only one or more of the numerous parameters and methods described above. Those skilled in the art can use other parameters to perform chemical mechanical polishing according to the above methods without departing from the core spirit of the disclosure.

[0116] [Data Measurement]

[0117] The TEOS removal rate (i.e., TEOS RR) was obtained by the following steps: 8-inch wafers with... The thickness was obtained from plasma-enhanced tetraethyl orthosilicate (PE-TEOS) deposition of silica wafers. The PE-TEOS wafers were polished for 30 seconds using a CTS-AP300 polishing tool (available from CTS Co.) at a polishing platform speed of 93 rpm, a carrier speed of 87 rpm, a film pressure of 3.3 psi, and a slurry flow rate of 150 ml / min. The material removal rate of the wafers was measured using an M-2000X ellipsometry (JAwollam), and the TEOS RR was calculated based on the thickness difference before and after polishing. The calculation results are listed in Table 2.

[0118] Preparation of needle-shaped cerium oxide abrasive grains

[0119] Preparation of needle-shaped cerium oxide abrasive particles A (e.g.) Figure 1 Needle-shaped cerium oxide abrasive particles A and Figure 2 (As shown): 200g of cerium nitrate (Ce(NO3)3·6H2O) was dissolved in 500mL of deionized water and stirred at room temperature until the solid dissolved; this solution is denoted as solution A. 300mL of ammonia water was dissolved in 400mL of deionized water and stirred until the solid dissolved; this solution is denoted as solution B. Solution B was slowly added to solution A while stirring at room temperature for 30 minutes. The mixture was placed in a water bath at 85℃ for 4 hours. The cooled mixture was centrifuged to obtain a white solid, which was then acidified with water and acetic acid to obtain a suspension of tangential octahedral cerium oxide. The needle-like cerium oxide abrasive particles A, measured by SEM, had an average length of 889nm and an average width of 83nm.

[0120] Preparation of needle-shaped cerium oxide abrasive particles B (e.g.) Figure 1 (As shown in needle-shaped cerium oxide abrasive particles B) 200g of cerium nitrate Ce(NO3)3·6H2O was dissolved in 500mL of deionized water and stirred at room temperature until the solid dissolved, denoted as solution A. 400mL of ammonia water was dissolved in 400mL of deionized water and stirred until the solid dissolved, denoted as solution B. Solution B was slowly added to solution A while stirring at room temperature for 30 minutes. The mixture was placed in a water bath at 85℃ for 4 hours. The cooled mixture was centrifuged to obtain a white solid, which was then acidified with water and acetic acid to obtain a suspension of tangential octahedral cerium oxide. The needle-shaped cerium oxide abrasive particles B, measured by SEM, had an average length of 1987nm and an average width of 173nm.

[0121] Example 1

[0122] Composition: The composition contains 0.5 wt% abrasive particles and 0.05 wt% pyridinecarboxylic acid. The pH is adjusted to 4.0 using ethanolamine. The composition is divided into A1, A2, E1, E2, E3, and E4 according to the different abrasive particles. A1 contains 100% chamfered octahedral cerium oxide abrasive particles (purchased). A2 contains 100% acicular cerium oxide abrasive particles. E1 contains 25% acicular cerium oxide abrasive particles and 75% chamfered octahedral cerium oxide abrasive particles. E2 contains 50% acicular cerium oxide abrasive particles and 50% chamfered octahedral cerium oxide abrasive particles. E3 contains 75% acicular cerium oxide abrasive particles and 25% chamfered octahedral cerium oxide abrasive particles. The chamfered octahedral cerium oxide abrasive particles in A1 are those described in Example 4, A5. The chamfered octahedral cerium oxide abrasives in E1, E2, and E3 are the same as those described in E7 of Example 4. The calcined chamfered octahedral cerium oxide abrasives in E4 are the same as those described in E9 of Example 4. The preparation of needle-shaped cerium oxide abrasives is as described above for needle-shaped cerium oxide abrasive B, and will not be repeated here.

[0123] The TEOS RR was measured using the above measurement method, and the results are listed in Table 2.

[0124] Table 2

[0125]

[0126] in conclusion:

[0127] Compared to compositions A1 and A3 containing only truncated octahedral cerium oxide abrasive particles and composition A2 containing only needle-shaped cerium oxide abrasive particles, compositions E1-E4 containing different proportions of needle-shaped cerium and truncated octahedrons exhibited higher TEOS removal rates. Furthermore, composition E4, containing calcined truncated octahedral cerium oxide abrasive particles, showed a higher removal rate than uncalcined truncated octahedral cerium oxide abrasive particles.

[0128] Example 2

[0129] Composition: The composition contains 0.5 wt% abrasive particles and 0.05 wt% pyridinecarboxylic acid. The pH is adjusted to 4.0 using ethanolamine. The composition is divided into A4, E5, and E6 according to the different abrasive particles. Specifically, the chamfered octahedral cerium oxide abrasive particles in A4 are the same as those described in A6 of Example 4. The chamfered octahedral cerium oxide abrasive particles in E5 and E6 are the same as those described in E8 of Example 4. The preparation of needle-shaped cerium oxide abrasive particles is as described above for needle-shaped cerium oxide abrasive particle A, and will not be repeated here.

[0130] Step height is Furthermore, different regions within the wafer have different linewidths. For example, the linewidth of active oxide is 500 micrometers, and the linewidth of trench oxide is 500 micrometers; the linewidth of active oxide is 200 micrometers, and the linewidth of trench oxide is 200 micrometers; the linewidth of active oxide is 100 micrometers, and the linewidth of trench oxide is 100 micrometers; the linewidth of active oxide is 50 micrometers, and the linewidth of trench oxide is 50 micrometers.

[0131] The polishing process is as follows: First, polish for 30 seconds to determine the polishing rate. Based on the determined polishing rate, calculate the removal of active oxides. The polishing time was determined based on the thickness, and this polishing time was used for polishing. After polishing, the remaining step height at the endpoint was measured, and the measurement results are shown in Table 3. The remaining step height at the endpoint was measured using an atomic force microscope (Park Instruments).

[0132] Table 3

[0133]

[0134] in conclusion:

[0135] Compared to A4, E5, with its mixed abrasive grains, exhibits a lower residual step height. This is because mixing needle-shaped cerium oxide abrasive grains with chamfered octahedral cerium oxide abrasive grains improves material removal rate and post-polishing flatness.

[0136] Example 3

[0137] Composition: The composition contains 0.5 wt% abrasive particles and 0.05 wt% pyridinic acid. The pH was adjusted to 4.0 using ethanolamine. The composition is divided into A5 and E7 based on the type of abrasive particles. The chamfered octahedral cerium oxide abrasive particles in A5 are those described in Example 4, A6. The chamfered octahedral cerium oxide abrasive particles in E7 are those described in Example 4, E8. The preparation of needle-shaped cerium oxide abrasive particles is as described above and will not be repeated here. It should be noted that the cerium oxide abrasive particles in E7 are mixed abrasive particles, and the ratio of needle-shaped cerium oxide abrasive particles to chamfered octahedral cerium oxide abrasive particles is 1:1. The zeta potential of the cerium oxide abrasive particles in composition A5 is 42 mV, and the zeta potential of the cerium oxide abrasive particles in composition A7 is 44 mV. The zeta potential was measured using a Nano ZSE (Malvern Instruments).

[0138] Step height is Furthermore, different regions within the wafer have different linewidths. For example, the linewidth of active oxide is 500 micrometers, and the linewidth of trench oxide is 500 micrometers; the linewidth of active oxide is 200 micrometers, and the linewidth of trench oxide is 200 micrometers; the linewidth of active oxide is 100 micrometers, and the linewidth of trench oxide is 100 micrometers; the linewidth of active oxide is 90 micrometers, and the linewidth of trench oxide is 90 micrometers; the linewidth of active oxide is 70 micrometers, and the linewidth of trench oxide is 70 micrometers; the linewidth of active oxide is 50 micrometers, and the linewidth of trench oxide is 50 micrometers; the linewidth of active oxide is 30 micrometers, and the linewidth of trench oxide is 30 micrometers; the linewidth of active oxide is 10 micrometers, and the linewidth of trench oxide is 10 micrometers.

[0139] The polishing process is as follows: First, polish for 20 seconds to determine the polishing rate. Based on this determined polishing rate, calculate the removal of active oxides. The thickness was determined and polished for the specified time. Then, it was polished three more times: 10 seconds each for the first, second, and third polishing cycles. After polishing, the remaining step height at the endpoint was measured, and the results are shown in Table 4. The remaining step height at the endpoint was measured using an atomic force microscope (Park Instruments).

[0140] Table 4

[0141]

[0142]

[0143] in conclusion:

[0144] Compared to A4, E7 exhibits a lower residual step height, which is achieved by mixing needle-shaped cerium oxide abrasive grains with chamfered octahedral cerium oxide abrasive grains, thereby improving material removal rate and post-polishing flatness.

[0145] Example 4

[0146] Preparation of chamfered octahedral cerium oxide abrasive grains

[0147] A6: Scanning electron microscope images of cerium oxide abrasive grains purchased from the market, as shown below. Figure 3 As shown.

[0148] E8: Preparation of uncalcined truncated octahedral cerium oxide

[0149] 200g of cerium nitrate (Ce(NO3)3·6H2O) was dissolved in 500mL of deionized water and stirred at room temperature until the solid dissolved; this solution is denoted as solution A. 100mL of ammonia solution was dissolved in 400mL of deionized water and stirred until the solid dissolved; this solution is denoted as solution B. Solution B was slowly added to solution A while stirring at room temperature for 30 minutes. The mixture was then placed in a water bath at 85℃ for 4 hours. The cooled mixture was centrifuged to obtain a white solid, which was then acidified with water and acetic acid to obtain a suspension of truncated octahedral cerium oxide. The scanning electron microscope image of the uncalcined truncated octahedral cerium oxide is shown below. Figure 4 As shown.

[0150] E9: Preparation of calcined truncated octahedral cerium oxide

[0151] The white solid obtained from the uncalcined truncated octahedral cerium oxide was placed in a high-temperature muffle furnace and calcined at 750 degrees Celsius for 2 hours to obtain a yellow solid powder. This powder was then ground, re-homogenized using high-shear dispersion, and finally obtained a suspension of calcined truncated octahedral cerium oxide. The scanning electron microscope image of the calcined truncated octahedral cerium oxide is shown below. Figure 5 As shown.

[0152] Particle size measurement

[0153] The average particle size of abrasive grains A6, E8, and E9 was evaluated using a NovaNano 450 scanning electron microscope. The average particle size was obtained by the arithmetic mean of the maximum distances between two points on the particle boundary measured from 1000 particles. As mentioned above, the coefficient of variation (CV) of the average particle size was obtained using the formula CV = (σ / μ) × 100% (where σ is the standard deviation of the average particle size and μ is the average particle size). The polydispersity index (PDI) was obtained using the formula PDI = σ 2 / μ 2 The values ​​are obtained and listed in Table 1. To obtain the ratio of (cumulative volume of particles exceeding twice the average particle size) / (cumulative volume of particles with the largest average particle size) in Table 1, the volume of the truncated octahedral cerium dioxide particles was calculated using the general mathematical formulas for square particles and spheres (using the assumption of spherical particles). Table 5 lists the properties of different truncated octahedral cerium oxide abrasives.

[0154] Table 5

[0155]

[0156] in conclusion:

[0157] As shown in Table 5, E8 and E9 have higher CVs compared to A6. This indicates that E8 and E9 have a wider particle size distribution. Compared to A6, E8 and E9 have higher PDIs, exceeding 0.1. This indicates that E8 and E9 have a polydisperse distribution, while A6 has a monodisperse distribution. Compared to A6, E8 and E9 have a significantly higher proportion of particles exceeding twice the average particle size. Compared to A6, E8 and E9 have a significantly higher cumulative volume of particles exceeding twice the average particle size (cumulative volume of particles exceeding twice the average particle size) / (cumulative volume of particles with the largest average particle size). This indicates that large particles constitute a large proportion of the total particle volume in E8 and E9.

[0158] Example 5

[0159] Chamfered octahedral cerium oxide (self-made, not post-calcined) and needle-shaped cerium oxide abrasives A and B were prepared as described above, and Raman spectroscopy analysis was performed on the particles. For Raman spectroscopy, the cerium oxide abrasives were centrifuged, the supernatant was removed, and the particles were dried overnight at 60°C. Raman spectra of the dried powder were applied to the powder using a 532 nm laser at 25°C using a Horiba HR550 spectrometer (Horiba). The spectra were baseline corrected using iterative reweighted least squares and normalized to the intensity of the F2g peak. The Raman spectra are as follows. Figure 1 As shown above, FWHM (full width at half height) and FWTM (full width at one-third of the maximum peak) are calculated and listed in Table 6.

[0160] Table 6

[0161]

[0162] in conclusion:

[0163] Compared to chamfered octahedral cerium oxide abrasives, needle-shaped cerium oxide abrasives exhibit larger FWHM and FWTM, indicating that the F2g peak of needle-shaped cerium oxide abrasives is wider.

[0164] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0165] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure may be presented by way of example only and may not be restrictive. Although not explicitly stated herein, those skilled in the art will understand that this specification requires various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this specification and are within the spirit and scope of the exemplary embodiments described herein.

[0166] Furthermore, certain terms in this specification have been used to describe embodiments of this specification. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this specification. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be suitably combined in one or more embodiments of this specification.

[0167] It should be understood that in the foregoing description of the embodiments in this specification, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the description and to aid in understanding a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may extract some features as individual embodiments when reading this specification. That is, the embodiments in this specification can also be understood as an integration of multiple sub-embodiments. It is also valid when each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0168] Every patent, patent application, publication of a patent application, and other material, such as articles, books, specifications, publications, documents, and literature (excluding any related historical examination documents), cited in this disclosure is incorporated herein for all purposes, including, for example, in the specification and claims of this disclosure. However, in the event of any inconsistency or conflict between the descriptions, definitions, and / or terms used in the foregoing and those used in this disclosure, the descriptions, definitions, and / or terms used in this disclosure shall prevail.

[0169] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments described in this specification. Other modified embodiments are also within the scope of this specification. Therefore, the embodiments disclosed in this specification are merely examples and not limitations. Those skilled in the art can implement the applications described in this specification using alternative configurations based on the embodiments in this specification. Therefore, the embodiments in this specification are not limited to the embodiments precisely described in the applications.

Claims

1. A chemical mechanical polishing composition for polishing a silicon oxide substrate, characterized by, Comprising: first abrasive particles, the first abrasive particles being needle-shaped ceria abrasive particles; and second abrasive particles, the second abrasive particles being ceria abrasive particles and different from the first abrasive particles.

2. The composition of claim 1, wherein, The second abrasive particles are truncated octahedral ceria abrasive particles.

3. The composition according to any one of claims 1 or 2, characterized in that, The weight ratio of the first abrasive particles to the second abrasive particles ranges from 1:9 to 9:1, wherein the first abrasive particles comprise between 10% and 90% of the total weight of the first and second abrasive particles, and the second abrasive particles comprise between 10% and 90% of the total weight of the first and second abrasive particles.

4. The composition of claim 3, wherein, The weight ratio of the first abrasive particles to the second abrasive particles ranges from 3:1 to 1:3, wherein the first abrasive particles comprise between 25% and 75% of the total weight of the first and second abrasive particles, and the second abrasive particles comprise between 25% and 75% of the total weight of the first and second abrasive particles.

5. The composition of claim 1, wherein, The average length of the first abrasive particles ranges from 500 nm to 3000 nm, as measured by scanning electron microscopy.

6. The composition of claim 1, wherein, The average width of the first abrasive particles ranges from 50 nm to 250 nm, as measured by scanning electron microscopy.

7. The composition of claim 2, wherein, The ratio of the cumulative volume of the second abrasive particles having an average particle size as measured by scanning electron microscopy that is more than twice the average particle size to the cumulative volume of the second abrasive particles having an average particle size as measured by scanning electron microscopy that is less than the average particle size is at least 0.

1.

8. The composition of claim 2, wherein, The coefficient of variation of the average particle size of the second abrasive particles as measured by scanning electron microscopy is greater than 30%.

9. The composition of claim 2, wherein, The second abrasive particles have a non-monodisperse particle size distribution as measured by scanning electron microscopy.

10. The composition of claim 2, wherein, The polydispersity index of the second abrasive particles as measured by scanning electron microscopy is at least 0.

1.

11. The composition of claim 2, wherein, At least 0.5% of the second abrasive particles have a particle size as measured by scanning electron microscopy that is more than twice the average particle size.

12. The composition of claim 1, wherein, The composition further comprises a polishing aid, the polishing aid comprising: a sugar alcohol to enhance the removal rate of the silica substrate.

13. The composition of claim 1, wherein, The one-third high full width at the F2g vibrational peak of the needle-shaped ceria abrasive particles in a Raman spectrum excited by a 532 nm laser is from 30 cm-1 to 200 cm-1.

14. The composition of claim 1, wherein, The one-third high full width at the F2g vibrational peak of the needle-shaped ceria abrasive particles in a Raman spectrum excited by a 532 nm laser is from 40 cm-1 to 130 cm-1.

15. The composition of claim 1, wherein, The half-high full width at the F2g vibrational peak of the needle-shaped ceria abrasive particles in a Raman spectrum excited by a 532 nm laser is from 10 cm-1 to 100 cm-1.

16. The composition of claim 1, wherein, The half-high full width at the F2g vibrational peak of the needle-shaped ceria abrasive particles in a Raman spectrum excited by a 532 nm laser is from 20 cm-1 to 80 cm-1.

17. The composition of claim 1, wherein, The half-high full width at the F2g vibrational peak of the needle-shaped ceria abrasive particles in a Raman spectrum excited by a 532 nm laser is greater than the half-high full width at the F2g vibrational peak of the second abrasive particles.

18. The composition of claim 1, wherein, The one-third high full width at the F2g vibrational peak of the needle-shaped ceria abrasive particles in a Raman spectrum excited by a 532 nm laser is greater than the one-third high full width at the F2g vibrational peak of the second abrasive particles.

19. A method for polishing a silicon oxide substrate, comprising: The method utilizes the composition of any one of claims 1-12 to polish a silica substrate.

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